#include<iostream>

using namespace std;

struct ListNode {
    int val;
    ListNode* next;
    ListNode() : val(0), next(nullptr) {}
    ListNode(int x) : val(x), next(nullptr) {}
    ListNode(int x, ListNode* next) : val(x), next(next) {}
    
};
class Solution {
public:
    ListNode* reverseList(ListNode* head) {
        if (head == nullptr || head->next == nullptr)
        {
            return head;
        }

        ListNode* newhead = reverseList(head->next);
        head->next->next = head;
        head->next = nullptr;
        return newhead;
    }
};

int main()
{
    return 0;
}